400131021 has 4 divisors (see below), whose sum is σ = 533508032. Its totient is φ = 266754012.

The previous prime is 400131019. The next prime is 400131029. The reversal of 400131021 is 120131004.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 400131021 - 2¹ = 400131019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400130988 and 400131006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400131029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66688501 + ... + 66688506.

It is an arithmetic number, because the mean of its divisors is an integer number (133377008).

Almost surely, 2^400131021 is an apocalyptic number.

It is an amenable number.

400131021 is a deficient number, since it is larger than the sum of its proper divisors (133377011).

400131021 is a wasteful number, since it uses less digits than its factorization.

400131021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133377010.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 400131021 is about 20003.2752568173. The cubic root of 400131021 is about 736.8867385279.

Adding to 400131021 its reverse (120131004), we get a palindrome (520262025).

The spelling of 400131021 in words is "four hundred million, one hundred thirty-one thousand, twenty-one".